The present invention relates to a spray oscillating control apparatus for sprinklers wherein two opposite inlet orifices of a water duct cooperatively work with covering blocks and water intake passageways of a spray control device, and a linkage gear wheel of the spray control device is directly meshed with one matched gear of a gear train assembly to rotate the covering blocks in linkage so as to switch the amount of intake water supply in a sequential order; thereby the spray control device can avoid being interfered by the water stream, and the gear train assembly can accurately rotate the spray control device in a smooth and efforts-saving manner.
Please refer to FIG. 1 showing a perspective cross sectional view of a conventional spray oscillating control apparatus for sprinklers. Such a spray oscillating control apparatus includes a sprinkling device 10 wherein water stream passing through an inlet port 11 is jetted towards a water wheel 12, causing the rotation of the water wheel 12 and the actuation of a gear shaft 13 therewith. Then, the gear shaft 13 will drive a worm gear 14 and cause a cylindrical wheel 15 fixed to the same axle to rotate with the worm gear 14 as well. A protruding shaft 161 abutted against a spiral guiding recess 151 of the cylindrical wheel 15 will be pushed by the rotation of the spiral guiding recess 151 and limited to move back and forth within an oval-shaped elongated slot 171 of a sliding seat 17. Accordingly, an integrally molded plug body 16 is forced to move back and forth towards or away from a water outlet orifice 18 so as to change the room of water discharge and, thus, vary the amount of water sprinkled through the water outlet orifice 18 thereof.
There are some disadvantages to such a conventional spray oscillating control apparatus for sprinklers. First, the water stream rotating the water wheel 12 must be projected under a sufficient water pressure so as to actuate the rotation of the cylindrical wheel 15 and the plug body 16 in a sequence. In case of a low water pressure, the water stream jetted towards the water wheel 12 becomes impotent to rotate the cylindrical wheel 15 and the plug wheel 16 which, subjected to interference from each other, tends to stop rotating in operation thereof. Second, when the plug body 16 moves back and forth within the sliding seat 17 thereof, water stream can infiltrate into the sliding seat 17 via the oval-shaped elongated slot 171. Therefore, even in case of a high water pressure, the water stream accumulated within the sliding seat 17 thereof can form a layer of resistance, causing the plug body 16 to be blocked thereby. Besides, the water wheel 12 can also be interfered by the plug body 16 and becomes hard to rotate in operation thereof.
Another conventional spray oscillating control apparatus for sprinklers is disclosed in the U.S. Pat. No. 4,860,954 wherein the sprinkler utilizes the rotation of an impeller to actuate the back-and-forth movement of a shaft, and an eccentric cam is disposed at one end of the shaft in communication with a tube. Most of all, the second prior art makes use of numerous assembly parts and is characterized by a complicated structure, which makes it rather difficult and time-consuming to assemble.